J. Buck Caldwell wrote:
> My employer has asked that I block access to instant messenger services
> like ICQ, MS Messenger, AIM, and YIM. I know ICQ used port 4000 at one
> time, is that still the case? What ports do these other services use?
> Any help would be appreciated. I checked IANA's well-known port list,
> but it wasn't much help - doesn't list any specific service except ICQ,
> which conflicts with another previously-registered service (which is why
> I was wondering if it changed).

I dont know off hand, but a place you could probably find out quickly
is jabber.org.  The Jabber server provides "transports" to the other
messanger services, allowing Jabber users to communicate with the IMs.
These transports are server side, so make sure you ask the right
people, ie general users wont know, so go to a server devel IRC
channel or mailing list.  Start here http://jabber.org/?oid=88